package x.y.z;

public class LeetCode_0141 {
    public boolean hasCycle(ListNode head) {
        if (head==null){
            return false;
        }

        ListNode slow=head;
        ListNode fast=head;

        while (fast!=null && fast.next!=null){
            slow=slow.next;
            fast=fast.next.next;
            if (slow==fast){
                return true;
            }
        }
        return false;
    }
}
